Explore the vast range of titles available.

Iron excess in tissues results in increased oxidative damage. Among different tissues, the skin can particularly be severely damaged by oxidative stress, as it is exposed not only to endogenous but also directly to exogenous pro-oxidants. The skin is especially vulnerable to harmful oxidative stress. Melatonin and indole-3-propionic acid (IPA), two indole substances, are efficient antioxidants. This study aims to evaluate the potential protective effects of melatonin and IPA against oxidative damage to membrane lipids (lipid peroxidation (LPO)), induced in porcine skin homogenates by the Fenton reaction (Fe2+ + H2O2 → Fe3+ + •OH + OH−) when iron is used in extremely high concentrations. Skin homogenates were incubated in the presence of FeSO4 (2400, 1200, 600, 300, 150 and 75 µM) + H2O2 (5 mM) with/without melatonin or IPA. LPO level (MDA + 4-HDA/mg protein) was measured spectrophotometrically. Melatonin, in its highest used concentration (5.0 mM), prevented FeSO4 (1200 mM)-induced LPO, whereas it was effective in concentrations as low as 2.5 mM against all lower iron concentrations. IPA was protective in concentrations as low as 2.5 mM independently of FeSO4 concentration. In conclusion, melatonin and IPA effectively protect against oxidative damage to membrane lipids induced by high concentrations of iron in porcine skin; therefore, both can be considered pharmacological agents in the case of disorders associated with excessive iron accumulation in the skin.

17β-estradiol plays a crucial role in regulating cellular processes in both reproductive and non-reproductive tissues, including the thyroid gland. It modulates oxidative stress and contributes to sexual dimorphism in thyroid diseases, with ROS production, particularly H2O2, generated by NOX/DUOX enzymes. This study aimed to investigate the effects of 17β-estradiol (10 nM or 100 nM) on the expression of NOX/DUOX, thyroid-specific genes, and endoplasmic reticulum (ER) stress-related genes in male and female porcine thyroid follicular cells. Expression of the studied genes was evaluated by RT-PCR before and after treatment with 17β-estradiol alone or with the addition of NOX4 inhibitor (GKT-136901). Additionally, the level of ROS was measured by flow cytometry analysis. Our results show that 17β-estradiol significantly upregulates thyroid-specific genes, particularly TPO, and stimulates NOX/DUOX expression, affecting the redox state of thyroid cells. It also stimulates ER stress-related genes such as CHOP. In conclusion, estrogen excess may contribute to thyroid disease development via such possible mechanisms as the upregulation of key thyroid-specific genes, particularly TPO, and of genes involved in the cellular response to ER stress, especially CHOP, as well as by the stimulation of the NOX/DUOX system with consequent ROS overproduction. These mechanisms may play a certain role in the higher prevalence of thyroid diseases in women.

Background: Vitamin D has a significant role in immune system regulation due to its profound impact on various immune cells, including Natural Killer T-like (NKT-like) cells. While previous studies have explored the effects of vitamin D on the overall NKT-like cell population, detailed investigations into its impact on specific NKT-like subpopulations are lacking. This study aimed to analyze the correlation between vitamin D levels and NKT-like cell subpopulations (CD4+CD8+; CD4-CD8+; CD4+CD8-; CD4-CD8-) in peripheral blood collected from patients without diseases that can influence vitamin D and/or calcium levels. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from 86 patients. NKT-like cells were separated from PBMCs using a CD3+ CD56+ NKT cell isolation kit and a magnetic bead separator. Flow cytometry (FC) was applied in order to evaluate the distribution of NKT-like cell subpopulations. Results: A significant positive correlation between vitamin D levels and the CD4-CD8+ NKT-like cell population, particularly the CD4-CD8high subtype was found. Importantly, this correlation was independent of calcium levels, emphasizing the unique impact of vitamin D on CD4-CD8+ NKT-like cells. Conclusions: Our findings suggest that vitamin D concentrations may influence the distribution of NKT-like cell subpopulations in peripheral blood, although further evidence is necessary to confirm this observation. These novel results provide a foundation for elucidating the mechanism underlying the effect of vitamin D on the immune system and may contribute to future therapeutic strategies targeting CD4-CD8+ NKT-like cells in immune and oncological disorders.

Sorafenib and lenvatinib are multi-targeted tyrosine kinase inhibitors which are currently approved to treat advanced hepatocellular carcinoma, renal cell carcinoma and radioiodine-refractory differentiated thyroid carcinoma. However this treatment is often limited due to common adverse events which may occur via oxidative stress. The study aims to compare sorafenib- and lenvatinib-induced oxidative damage to membrane lipids (lipid peroxidation, LPO) in homogenates of porcine noncancerous tissues of the thyroid, the liver, and the kidney and to check if it can be prevented by antioxidants melatonin and indole-3-propionic acid (IPA). Homogenates of individual tissues were incubated in the presence of sorafenib or lenvatinib (1 mM, 100 µM, 10 µM, 1 µM, 100 nM, 10 nM, 1 nM, 100 pM) together with/without melatonin (5.0 mM) or IPA (5.0 mM). The concentration of malondialdehyde + 4-hydroxyalkenals, as the LPO index, was measured spectrophotometrically. The incubation of tissue homogenates with sorafenib resulted in a concentration-dependent increase in LPO (statistically significant for concentrations of 1mM and 100 µM in the thyroid and the liver, and of 1 mM, 100 µM, and 10 µM in the kidney). The incubation of thyroid homogenates with lenvatinib did not change LPO level. In case of the liver and the kidney, lenvatinib increased LPO but only in its highest concentration of 1 mM. Melatonin and IPA reduced completely (to the level of control) sorafenib- and lenvatinib-induced LPO in all examined tissues regardless of the drug concentration. In conclusion, sorafenib comparing to lenvatinib is a stronger damaging agent of membrane lipids in noncancerous tissues of the thyroid, the liver, and the kidney. The antioxidants melatonin and IPA can be considered to be used in co-treatment with sorafenib and lenvatinib to prevent their undesirable toxicity occurring via oxidative stress.

Mannan-binding lectin (MBL) is a main component of the lectin pathway of the complement system. Although there are some studies showing links between endocrine and immune systems, the ones concerning hypopituitarism are limited. The aim of this study was to check whether there is any association between blood MBL level and pituitary hormone deficiencies and whether this relationship is affected by appropriate hormone replacement therapies. One hundred and twenty (120) inpatients, aged 18-92, were divided into two main groups, control individuals (21/120) and patients with pituitary diseases (99/120). The latter were diagnosed either with hypopituitarism (n=42) or with other pituitary diseases (not causing hypopituitarism) (n=57). Additionally, hypopituitary patients on appropriate replacement therapies (compensated hypopituitarism) were compared to patients on inappropriate replacement therapies (non-compensated hypopituitarism). Several parameters in blood serum were measured, including MBL level, pituitary and peripheral hormones and different biochemical parameters. Serum MBL level was significantly lower in patients with hypopituitarism comparing to controls (1358.97 ± 244.68 vs. 3199.30 ± 508.46, <0.001) and comparing to other pituitary diseases (1358.97 ± 244.68 vs. 2388.12 ± 294.99, 0.015) and this association was confirmed by univariate regression analysis. We evaluated the distribution of patients with relation to MBL level; there was a clear difference in this distribution between control individuals (among whom no subjects had MBL level <500 ng/mL) and patients with hypopituitarism (among whom 43% of patients had MBL level <500 ng/mL). Moreover, patients with non-compensated hypopituitarism had lower mean and median MBL levels comparing to patients with compensated hypopituitarism (1055.38 ± 245.73 vs. 2300.09 ± 579.93, 0.027; 488.51 vs. 1951.89, 0.009, respectively) and this association was confirmed in univariate regression analysis. However, mean and median MBL levels in patients with compensated hypopituitarism vs. controls did not differ significantly (2300.09 ± 579.93 vs. 3199.30 ± 508.46, 0.294; 1951.90 vs. 2329.16; 0.301, respectively). Hypopituitarism in adults is associated with a decreased blood concentration of mannan-binding lectin, a phenomenon which does not exist in hypopituitary patients on the appropriate hormone replacement therapies. Therefore measurement of mannan-binding lectin level in patients with hypopituitarism may be considered as a parameter contributing to adjust optimal doses of hormone replacement therapies.

Sexual dimorphism significantly influences the epidemiology of thyroid disorders, with females exhibiting higher incidence of thyroid diseases. Estrogens and their hydroxylated metabolites are key regulators of cellular redox balance and may contribute to sex-specific susceptibility through pro-oxidative mechanisms. However, the impact of individual estrogen metabolites on oxidative stress in thyroid follicular cells remains poorly defined. Here, we investigated the pro-oxidative effects of 17β-estradiol (E2) and its hydroxylated metabolites-2-hydroxyestradiol (2-OHE2), 4-hydroxyestradiol (4-OHE2), and 16α-hydroxyestrone (16α-OHE1)-in primary porcine thyroid cell cultures from males and females. Primary follicular thyroid cells were isolated from six male and six female pigs. Cells were exposed to E2 (100 nM) or its metabolites (1 μM), with or without Fenton reaction substrates (Fe and H O ), for 24 h. Lipid peroxidation (an index of oxidative damage to lipids) was quantified using BODIPY 581/591 C11 fluorescence via flow cytometry. Basal lipid peroxidation did not differ between sexes. 2-OHE2 increased lipid peroxidation in both male and female thyroid cells, with a more pronounced effect observed in males. In contrast, 4-OHE2 selectively enhanced lipid peroxidation only in female cells. 16α-OHE1 elevated lipid peroxidation in both sexes. E2 significantly increased lipid peroxidation in both male and female cells. Among all compounds tested, E2 exhibited the most potent pro-oxidative activity, particularly in female-derived cells. These findings provide novel insights into the redox-modulating effects of estrogen metabolism in the thyroid and suggest a potential molecular basis for sex-related susceptibility to thyroid dysfunction. While based on an in vitro porcine model, the study increases our understanding of the mechanisms by which estrogenic compounds may influence thyroid pathophysiology, possibly including early events in thyroid disease development or oncogenesis.

The thyroid gland is the primary site of sodium/iodide symporter (NIS), an intrinsic plasma membrane protein responsible for the active uptake of iodine, which is indispensable for thyroid hormone synthesis. Since exposure of the thyroid to NIS inhibitors can potentially have harmful effects on the entire organism, it is important to investigate the potential protective effects of known antioxidants, such as melatonin and indole-3-propionic acid (IPA), against pro-oxidative action of classic NIS inhibitors. The study aimed to check if and to what extent melatonin and IPA interact with some confirmed NIS inhibitors regarding their effects on oxidative damage to membrane lipids in the thyroid. For comparison with the thyroid gland, in which NIS is typically present, the liver tissue—not possessing NIS—was applied in the present study. Thyroid and liver homogenates were incubated in the presence of tested NIS inhibitors (i.e., NaClO3, NH4SCN, KSeCN, KNO3, NaF, KClO4, and BPA) in different ranges of concentrations with/without melatonin (5 mM) or IPA (5 mM). The malondialdehyde+4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. NaClO3 increased LPO in the thyroid and in the liver, but these pro-oxidative effects were not prevented by either melatonin or IPA. Instead, pro-oxidative effects of NH4SCN observed in both tissues were prevented by both indole substances. KSeCN and NaF increased LPO only in the thyroid, and these pro-oxidative effects were prevented by melatonin and IPA. KNO3, KClO4, and BPA did not increase LPO, which can be due to their low concentrations resulting from restricted solubility. In conclusion, as melatonin prevented oxidative damage to membrane lipids in the thyroid caused by some sodium/iodide symporter inhibitors, this indoleamine shoud be considered as a potential protective agent when produced appropriately in living organisms but also as an exogenous substance recommended to individuals overexposed to NIS inhibitors.

Background: Central hypothyroidism is characterized by either decreased TSH or, more commonly, normal TSH. This study aims to check whether this biochemical difference related to the severity of the pituitary disease, metabolic processes and general well-being. Methods: A retrospective analysis was performed on 108 inpatients with hypopituitarism, aged 18–80, hospitalized (1 January 2020, through 31 December 2022) in the Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Poland. Hypopituitary patients with central hypothyroidism (n = 90) were divided into two subgroups: patients with TSH below normal ranges (low TSH; n = 52) and patients with TSH in reference ranges (normal TSH; n = 38). Results: Among patients with central hypothyroidism, surgical treatment due to pituitary disease was performed more commonly in those with low TSH than in those with normal TSH (65 vs. 42%, p = 0.010). Expectedly, five pituitary deficiencies were diagnosed more commonly in patients with low TSH than in those with normal TSH (46 vs. 13%, p = 0.001). In a regression analysis, the ACTH concentration was the only independent determinant negatively associated with low TSH (also after limiting the analysis to non-treated patients). Regarding lipid profile, decreased HDL cholesterol occurred more commonly in patients with low TSH vs. normal TSH (44% vs. 23%; p = 0.033), which was also observed after the limitation to non-treated patients (47% vs. 21%; p = 0.013). Conclusions: Low TSH in patients with central hypothyroidism is associated with more advanced pituitary disease and less favorable metabolic profile.

It is well-known that thyroid diseases are more prevalent in women than in men. The contribution of sex hormones may explain such disparity. The aim of this study was to check if there are any differences between sexes concerning the effects of 17β-estradiol on oxidative damage to membrane lipids (lipid peroxidation) in porcine thyroid homogenates under basal conditions and in the presence of Fenton reaction (Fe2+ + H2O2→Fe3+ + •OH + OH−) substrates. We observed that 17β-estradiol did not change the basal level of lipid peroxidation (measured spectrophotometrically as concentrations of malondialdehyde + 4-hydroxyalkenals) in thyroid homogenates, and no differences were found between sexes. The lipid peroxidation level in response to Fe2+ + H2O2 plus 17β-estradiol was lower in male thyroids. In turn, in male thyroids, 17β-estradiol reduced experimentally induced lipid peroxidation in as low of a concentration as 0.1 μM, whereas in female thyroids the lowest effective concentration of 17β-estradiol was 10 μM, i.e., 100 times higher than in males. In conclusion, the protective effects of exogenous 17β-estradiol against experimentally induced oxidative damage to membrane lipids is stronger in male than in female thyroids. Our observation suggests that female tissue is less sensitive to the protective effects of exogenous 17β-estradiol. This sexual dimorphism of oxidative processes in the thyroid may constitute one of the mechanisms of the different prevalence of thyroid diseases in women and in men.

Whereas oxidative reactions occur in all tissues and organs, the thyroid gland constitutes such an organ, in which oxidative processes are indispensable for thyroid hormone synthesis. It is estimated that huge amount of reactive oxygen species, especially of hydrogen peroxide (H 2 O 2 ), are produced in the thyroid under physiological conditions, justifying the statement that the thyroid gland is an organ of “oxidative nature”. Apart from H 2 O 2 , also other free radicals or reactive species, formed from iodine or tyrosine residues, participate in thyroid hormone synthesis. Under physiological conditions, there is a balance between generation and detoxification of free radicals. Effective protective mechanisms, comprising antioxidative molecules and the process of compartmentalization of potentially toxic molecules, must have been developed in the thyroid to maintain this balance. However, with additional oxidative abuse caused by exogenous or endogenous prooxidants (ionizing radiation being the most spectacular), increased damage to macromolecules occurs, potentially leading to different thyroid diseases, cancer included.